云南、四川省有螺无病地区钉螺对日本血吸虫易感性研究(英文)

SUSCEPTIBILITY OF ONCOMELANIA SNAILS FROM SNAIL EXISTENT NON ENDEMIC AREAS OF SCHISTOSOMIASIS TO SCHISTOSOMA JAPONICUM MIRACIDIA IN YUNNAN AND SICHUAN PROVINCES 

目的：为阐明大山区（云南和四川省）有钉螺而无日本血吸虫病流行地区（简称：有螺无病地区）钉螺在流行病学中的意义及为制定防治方案提供依据。方法：选择大山区４个有代表性有螺无病村的钉螺，以所在省的日本血吸虫毛蚴在实验室进行群体感染，钉螺与毛蚴比例分别为１∶４０和１∶９０。结果：４个有螺无病村的钉螺均能为日本血吸虫毛蚴感染，其中，四川省两个有螺无病村钉螺体内的日本血吸虫毛蚴可发育至尾蚴阶段。结论：云南、四川省有螺无病地区钉螺在适宜的环境和一定数量的传染源的条件下可以为所在省的血吸虫毛蚴感染，大山区有螺无病地区为潜在的日本血吸虫病流行区，应加强对这类地区日本血吸虫传染源输入的监测工作。

AIM: To clarify the epidemiological status of schistosomiasis in snail existent non endemic areas of the disease(SENEAS) in mountainous regions, and to provide a background for modification of control strategies. METHOD: Four typical counties were selected as pilot areas, that is, Lijiang and Yongsheng counties, Yunnan Province, and Mingshan and Jianyang counties, Sichuan Province. Oncomelania snails collected from the pilot areas were exposed to miracidia of S. japonicum from endemic areas of respective provinces at the ratio of 1 to 40 or 1 to 90. RESULTS: Oncomelania snails from all the four pilot areas ( villages) could be infected with miracidia, and the larvae could develop to cercarial stage in snails from Sichuan. :CONCLUSION Oncomelania snails in SENEAS in Yunnan and Sichuan provinces could be infected by S.japonicum miracidia from endemic areas of respective provinces in appropriate environment. Adequate measures should be undertaken to prevent the imported infection sources, so as to elude the alteration of SENEAS into endemic area. It is likely that SENEAS in mountainous areas would change into endemic regions in the case of existence of sufficient sources of infection. So control of and surveillance on the imported schistosome infection should be intensified.